Process for the manufacture of shaped bodies from viscose, and the products thus obtained



United States Patent l PRQCESS FQR THE MANUFACTURE OF SHAPED BGDIlES FRQM VESCOfiE, AND TEE PRGDUCTS THUS QBTAJNED Albeit Willem ilacoh van Doom and Adrianus Marinus van de Ven, Arnhem, Netherlands, assignors to American Erika Corporation, Eulra, N.C., a corporation of Delaware No Drawing. Filed Sept. 1, 1% Ser. No. 135,457

13 Claims. (Cl. 264-491) This invention relates to improvements in the production of shaped bodies of regenerated cellulose rayon from viscose. This invention also relates to an improved viscose spinning solution. More particularly, this invention relates to the'produetion of films, fibers, threads, filaments and the like products from an improved viscose rayon spinning solution.

In conventional methods of producing shaped bodies from viscose, a suitable cellulosic material, such as wood pulp, is first converted into an alkali'cellulose by treatment with a caustic soda solution. Thereafter, the treated cellulose is shredded and allowed to age. After ageing, the alkali cellulose is converted into cellulose xan'thate by treatment with carbon disulfide. The cellulose xanthate is subsequently dissolved in a caustic soda solution in an amount sufiicient to provide a viscose of the desired cellulose and alkali content. After infiltration, the viscose solution is allowed to ripen and is then extruded through a shaped orifice into a suitable coagulating and regenerating bath.

In the production of shaped bodies such as filaments, the viscose solution is conventionally extruded through a spinneret into a coagulating and regenerating bath consisting of an aqueous acid solution containing zinc sulfate. Thereafter, the filament is passed through a hot aqueous bath where it is stretched to improve its tensile strength. The filament may then be subjected to a dilute aqueous solution of sulfuric acid and sodium sulfate to complete the regeneration of the cellulose in the case where it is not completely regenerated upon leaving the stretching stage. The filament is subsequently subjected to washing, purification, bleaching, and drying treatments.

The threads and fidar'nents formed by these conventional methods consist of a skin or outer shell portion and a core portion with a line of demarcation between the two. These threads and filaments will hereinafter be referred to as threads and filaments having a socalled skin structure.

In the conventional process for making tire cord, a

number of threads, as obtained from a spinning operation,

are combined and plied. In such processes, it is well known that a loss of strength will occur as a result of the plying operation. That is, the strength of the manufactured cord as well as the double loop strength, is lower than the sum of the strength values of'the component threads. Such losses of strength dueto the threads being processed into cord will hereinafter be referred to as cord losses.

Moreover, it is well known that by using polymers of epoxyalkanes having a certain composition and mean molecular weight, that is, polymers of epoxyethane having a mean molecular weight between 3,800 and 4,286, these cord losses may be reduced.

3,151 ,l94 Patented Sept. 29, 1964 In accordance with the process of the present invention it has unexpectedly been found that threadscan be produced with the occurrence of even smaller cord losses by the addition of a polythiodiglycol to the viscose before being spun in a sulphuric acid spinning bath containing at least 2% by weight zinc sulphate. In addition, this new process offers the advantage that the strength of the threads and the resistance to abrasion obtained is greater, and the swelling value lower, than the respective values for the threads obtained heretofore in the prior art processes. Moreover, the threads obtained according to this invention have the additional advantage over the polyepoxyethane modified threads in that they have a higher resistance to heat. This property is of particular .importance for tire cords. Furthermore, the above-mentioned higher strength of the threads can be obtained while using lower acid concentrations in the spinning bath.

It is therefore an object of this invention to provide a method for making regenerated cellulose viscose rayon threads, fibers, films, yarns, cords and the like products having improved physical properties by utilizing a novel combination of modifiers.

Another object is to provide a new viscose spinning solution.

It is still another object of the invention to provide a new viscose spinning solution containing novel modifiers.

A further object of this invention is to provide threads, filaments and cords from an improved viscose spinning solution.

till another object of this invention is to provide tire cords having high double loop strength and high resistance to abrasion.

It is still a further object of this invention to provide fibers having an improved washing fastness.

Other objects will be apparent from the following detailed description.

In accordance with this invention, artificial threads. filaments, fibers, films and the like products are manufactured from a viscose solution containing at least one polythiodiglycol. These compounds containing etheral oxygen and sulfur are first added to a viscose solution and then spun into a sulfuric acid spinning bath containing at least 2% by weight of zinc sulfate.

The term polythiodiglycol as employedlherein in the specification and claims isintended to refer to the polymers formed by the condensation of thiodigiycols of the formula HOC H -S-C ,H OH alone or in the presence of similar glycols, wherein n is aninteger 2, 3, or 4. The term polythiodiglycol is employed in the generic sense; when it is intended to refer to a polymer prepared from a specific thiodiglycol of the above formula, the resultant polymer is referred to as a C -ipolythiodiglycol to indicate whether it is 2, 3, or 4. The condensation suitably may be carried out in'the presence of a dehydrating catalyst. A specific example of the polythiodiglycols used'in the present invention is the C -polythiodiglycol prepared by condensing thiodiglycol at a temperature of about to about 200C. in the presence of a dehydrating catalyst like hydrochloric acid. This reaction may also takeplace in the presence of glycols.

A tln'odiglycol polymer is preferred in which the number of etheral oxygen and sulphur atoms are practically r 3 equal and wherein the polymer has a mean molecular weight between about 700 and 1,250.

In accordance with this invention it is possible to combine polythiodiglycols prepared in the absence of glycols with polyglycols to obtain a mixture wherein the oxygen and sulphur content may be varied in a way which is comparable with the variation which may be obtained by copolymerization of thiodiglycol and glycols within the molecule.

The polyglycols may be homopolyrners', copolymers or block polymers. An example of a block polymer is:

wherein b is equal to 30 and the sum of a plus is equal to 85. Therefore, by combining such polythiodiglycols and polyglycols it is possible to obtain artificial products having improved swelling value, strength, and resistance to heat compared with the products obtained from viscoses employing only the polyglycols or the polythiodiglycols alone. A preferred form of the polyglycols is polyepoxyethane which has a mean molecular weight of about 3,000.

An example of a viscose to which a mixture of a polythiodiglycol and a polyglycol has been added is a viscose containing 0.1% by weight (calculated on the weight of the viscose) of polyethylene oxide with a mean molecular weight of 3,000 and 0.1% by weight of polythiodiglycol with a mean molecular weight of 1,200.

In addition to the polythiodiglycols being combined with polyglycols, they may also be combined with one or more amine compounds of the formula:

where R is an aliphatic chain with at least 8 carbon atoms, n is 2, 3 or 4, v-l-w is at least 2, and neither v nor w may be zero. The quaternary ammonium derivatives of these compounds may also be used when combined with polythiodiglycols the substituted amines are preferred in an amount ranging from about 25% to about 60% of the combined weights of the polythiodiglycols and the amines.

Examples of these amines are the products that are commercially available under the names Ethomeen C/ 15, Ethomeen C/ 20, Ethomeen C/ 25, Ethomeen C/ 60, Ethomeen S/ 15, Ethomeen S/20, Ethomeen S/25, Ethomeen 5/60, Ethomeen 2/15, Ethomeen T/ 20, Ethomeen T/25, Ethomeen T/ 60 and Huls V 1011 T. Examples of the quaternary ammonium derivatives are the compounds that are available under the trade name Ethoquads.

The Ethomeens are prepared by reacting amines derived from higher fatty acids with ethylene oxide. In this way the C-Ethomeens are derived from coconut oil, the S-Ethomeens from soy-bean oil and the T-Ethomeens from tallow. The numbers 15, 20, 25 and 60 following the capital US, Ss and TS indicate, after a deduction by 10, the number of ethylene oxide molecules that have been reacted with one molecule of the amine.

Huls V 1011 T is a representative of the groups of compounds of the formula:

plication of a mixture of polythiodiglycols and polyglycols, a less smooth surface is obtained. A smooth surface attracts and retains less dirt and foreign matter. After 4 such smooth threads have been cut into staple, they are very suitable for use as carpet fibers. These staple fibers moreover, exhibit good wash fastness.

The polythiodiglycols, with or without the polyglycols or amines, may be added to the cellulose itself, or they may be added at any random stage in the preparation of the viscose. It is preferred that this addition be made after the cellulose xanthate has dissolved. These substances may, moreover, be added in concentrated form or after they have been dissolved in an alkali hydroxide or after they have been diluted with water. It is preferred that these modifiers be employed in an amount equal to about 0.03 to about 1.0% based on the weight of the viscose.

The composition of the viscose may vary within wide limits as far as the cellulose and alkali contents are concerned. It is preferred that the cellulose content be maintained between about 4 and about 8% by weight and the alkali content may also be maintained between the same limits.

Although spinning baths with a higher sulphuric acid content may be used, that is, baths containing up to 10% by weight or more of sulphuric acid, it has been found favorable, in connection with the desirable strength and water swelling properties of these threads to use spinning baths in which the sulphuric acid content is less than 7% by weight.

Preferably, the cellulose and alkali values are so chosen that the acid content of the spinning bath is less than 5.5% by weight and not higher than 1.2 times the alkali content of the viscose. The carbon disulphide content of the viscose is preferably chosen between about 26 and about 42% by weight, as calculated on the weight of the cellulose. It has also been found possible that the viscose modified according to this invention may be spun with an acid concentration that is below the acid concentration of the spinning bath.

In accordance with this invention, it is necessary that at least 2% by weight of zinc sulphate be employed. Above this minimum value of 2% by weight, the zinc content in the spinning baths may vary considerably and may be as much as 10% by weight or more. For reasons of economy, however, the lower percentages are preferred.

The stretching or drawing which is necessary forobtaining threads having the properties desired may be carried out in a single bath process as well as in a two bath process, that is, the stretching may be carried out in one or more stages. The length of the stretching zone in such a second bath of the two bath process is usually chosen such that at the end of the stretching process the cellulose xanthate is to a large extent decomposed, preferably to a cellulose xanthate ratio of not more than about 0.02. By the xanthate ratio, which is determined according to the method also known for the determination of the gamma number, is meant the ratio of the number of xanthate radicals still present to the total number of the glucose radicals (C H O In accordance with this invention, it has been unexpectedly found when the viscose spinning solution contains a polythiodiglycol, a polyglycol and an amine, it has been found that the fibers, films, filaments, threads, cords and like products thus obtained exhibit greater tensile strength, lower cord losses, a greater abrasion resistance, lower swelling values, higher heat resistance, lower dirt retention, a smoother surface structure and greater wash fastness than the respective values for similar shaped bodies obtained according to prior art processes.

The invention will be further explained with reference to the following examples which are to be regarded by no means as restrictive. In these examples the composition of the viscose, the spinning bath, etc., is expressed in percentages by weight.

Example I A viscose spinning solution was prepared with a cellulose content of 7.5%, an alkali content of 5.8% and 0.1%

of C -polyt hiodiglycol (calculated on the weight of the viscose) with a mean molecular weight of about 1,000. The solution, with a xanthate ratio'of 0.43 and a viscosity of 80 seconds (determined by the falling sphere method), was spun into an aqueous spinning bath maintained at 55 C. This bath contained 5.8% of sulphuric acid, 11.0% of sodium sulphate and 5.0% of zinc sulphate. The thread was immersed for a distance of 100 cm. in this bath while passing through a tube consisting of two sections measuring 60cm. and 20cm. in length, respectively, and measuring 20 mm. and 40 mm.,'respectively, in diameter. The freshly spun threadwas withdrawn from the spinning bath and was then stretched 50% in the atmosphere and was subsequently stretched 50% in a second bathcontaining 3.0% H 80 and less than 1.0% of salts. The temperature of the second bath was 95 C. and the length of immersion in this bath was 120 cm. The thread was subsequently wound onto a bobbin at a speed of 40 meters per minute. The thread thus obtained was then washed free from acid in the usual manner, sized and then dried under tension. Thereafter, the physical properties were determined. The thread, which had a total tex (calculated as of the denier) of 200 and consisted of 1000 filaments, was found to have a swelling value of 67%.

Example II A viscose was prepared containing 5.5% by weight of cellulose, .5% by weight of sodium hydroxide, and containing 0.1% of polyethylene oxide with a mean molecular weight of 1,500 as well as 0.1 of C -polythiodiglycol with a mean molecular weight of 800. While at a xanthate ratio of 0.46 and a viscosity of 120 seconds (falling sphere method), the viscose was spun through a spinning nozzle having 1,200 holes, each measuring 60 microns in diameter, into a spinning bath maintained 50 C. This spinning bath contained 5.0% sulphuric acid, 15.0% sodium sulphate and 6.0% zinc sulphate.

The freshly spun threads passed through a tube as described in Example I and covered a distance of 100 cm. The threads were then withdrawn from the spinning bath and stretched 95% in a second bath maintained at 95 C. and containing 3.0% sulphuric acid. The length of immersion in this bath was 150 cm.

After the threads had been stretched they were collected at a rate of 40 meters per minute in a spinning pot and subsequently washed, subjected to an after treatment and dried in the usual manner. The threads thus manufactured had a swelling value of 63%.

These threads were then heated for 16 hours at 165 C. Thereafter it was noted that their strength had decreased to approximately 80% of the original value. On the other hand, threads obtained from viscose mixed exclusively with 0.2% of polyethylene oxide, were found to have a strength equal to only about 70% of the original value.

Example III A viscose was prepared containing 7.5% by weight of cellulose, 5.8% by weight of sodium hydroxide, and containing 0.1% of C -polythiodiglycol with a mean molecular weight of 1,200, as well as 0.1% of the commercially available Ethomeen C/ 25. While at a xanthate ratio of 0.44 and a viscosity of 90 seconds (falling sphere method), this viscose was spun through a spinning nozzle having 1650 holes each measuring 50 microns in diameter, into a spinning bath maintained at 50 C. and containing 5.2% by weight of sulphuric acid, 14.0% sodium sulphate, 6.0% zinc sulphate and 0.005% lauryl pyridinium sulphate.

The freshly spun threads passed through a tube like that described in Example I and covered a distance of 100 cm. The threads were then withdrawn from the spinning bath and were stretched 95% in a second bath 120 cm. in length and containing 3.0% sulphuric acid. This bath was maintained at a temperature of 95 C.

After the threads had been stretched they were collected at a rate of 30 meters per minute in a spinning pot and subsequently washed, subjected to an after-treatment and dried in the usual manner. 'The threads thus manufactured had a swelling value of 65%. When the threads were processed into cord, the cord loss was only 18%, as compared with 25% if no Ethomeen had been used in the viscose.

While preferred embodiments of the invention have been disclosed, the description is intended to be illustrative only and it is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as defined by the appended claims.

What is claimed is:

1. A process for the manufacture of viscose rayon thread which comprises adding to a viscose solution a small amount of a polythiodiglycol selected from the group consisting of the polymers formed by the condensation of thiodiglycols of the formula wherein n is an integer selected from the group consisting of 2, 3 and 4, and polymers formed by the condensation of said thiodiglycols in the presence of glycols corresponding thereto, and spinning the resultant viscose solution into a sulfuric acid coagulating bath containing at lea-st 2.0% by weight of zinc sulfate to form smooth threads, said small amount of said polythiodiglycol being efiec-tive to provide threads having improved strength, abrasion and heat resistance, lower swelling value and when twisted into cord has lower cording losses.

2. A process according to claim 1 in which preliminary to said spinning step from about 0.03 to about 1.0% by Weight, based on said viscose, of an ethoxylated amine having the following structural formula:

(CDH DH) H wOnHho) wH wherein R is an aliphatic chain with at least 8 carbon atom-s, n is 2-4, and the sum of v plus w is at least equal to 2 also is added to said viscose solution.

3. A process according to claim 1 wherein the amount of said polythiodiglycol employed is in the range of from about 0.03 to about 1.0% by Weight, based on said visco-se.

4. A process according to claim 1 wherein said polythiodiglycol is a homopolymer of 5. A process according to claim 1 wherein said polythiodiglycol has .a mean molecular Weight in the range of from about 700 to about 1,250.

6. A process according to claim 1 wherein said polythiodiglycol is a homopolymer of having a mean molecular weight in the range of from about 700 to about 1,250 and is employed. in an amount in the range of from about 0.03 to about 1.0% by Weight based on said viscose.

7. A process according to claim 2 wherein the amount of said polythiodiglycol employed is in the range of from about 0.03 to about 1.0% by weight, based on said viscose, R is in the range of from about 8 to about 24, n is 2, and the sum of v plus w is in the range of from about 5 to about 50.

8. A process according to claim 7 wherein said polythiodiglycol has a mean molecular Weight in the range of from about 700 to about 1,250.

9. A process according to claim 8 wherein said polythiodiglycol is a homopolymer of 10. A process according to claim 1 wherein preliminary 13. A process according to claim 12 wherein said polyto said spinning step from about 0.03 to about 1.0% thiodiglywlis ahomopolymer of by weight, based on said viscose, of a polyethylene oxide HO %CH2%2S CH2 }2 OH also is added to said viscose solution.

11. A process according to claim 10 wherein the References Cited in the file Of this Patellt amount of said polythiodiglycol employed is in the range UNITED STATES PATENTS of from about 0.03 to about 1.0% by weight based on said 2,392,103 Schlosser et a1 Jam 1 1946 viscose, and said polyethylene oxide has a mean molecu- 2,393,817 Schlosser et a1 Jam 29, 1946 lar weight in the range of from about 1,500 to about 10 2 9 423 i i h 7 1954 2,852,333 Cox et a1 Sept. 16, 1958 12. A process according to claim 11 wherein said poly- 2,912,299 Drisch et a1. Nov. 10, 1959 thiodiglycol has a mean molecular weight in the range 2,962,341 Cox Nov. 29, 1960 of from about 700 to about 1,250. 2,983,572 El1ing et a1. May 9, 1961 

1. A PROCESS FOR THE MANUFACTURE OF VISCOSE RAYON THREAD WHICH COMPRISES ADDING TO A VISCOSE SOLUTION A SMALL AMOUNT OF A POLYTHIODIGLYCOL SELECTED FROM THE GROUP CONSISTING OF THE POLYMERS FORMED BY THE CONDENSATION OF THIODIGLYCOLS OF THE FORMULA HO--CNH2N--S--CNH2N--OH WHEREIN N IS AN INTEGER SELECTED FROM THE GROUP CONSISTING OF 2,3,4, AND POLYMERS FORMED BY THE CONDENSATION OF SAID THIODIGLYCOLS IN THE PRESENCE OF GLYCOLS CORRESPONDING THERETO, AND SPINNING RESULTANT VISCOSE SOLUTION INTO A SULFURIC ACID COAGULATING BATH CONTAINING AT LEAST 2.0% BY WEIGHT OF ZINE SULFATE TO FORM SMOOTH THREADS, SAID SMALL AMOUNT OF SAID POLYTHIODIGLYCOL BEING EFFECTIVE TO PROVIDE THREADS HAVING IMPROVED STRENGTH, ABRASION AND HEAT RESISTANCE, LOWER SWELLING VALUE AND WHEN TWISTED INTO CORD HAS LOWER CORDING LOSSES. 